ch 2- cells Flashcards
living thing
anything that can move, respire, sense, grow, reproduce, equilibrium, excrete waste and take up nutrients
homeostasis
the maintenance of a relatively stable internal environment in the body, despite changes in the external environment
organism
living things made up of one or more cells
cell theory
- all living things are made up of cells
- cells are the smallest and most basic units of life
- all cells come from pre existing cells
prokaryotes
group of single-celled organisms with no nucleus and a circular loop of DNA. bacteria and arachaea are both prokaryotic
eukaryotes
a group of single and multicelled organisms with a nucleus and linear strands of DNA. animals, plants, fungi and protists are eukaryotics
plasma membrane
the phospholipid bilayer and embedded proteins which separate the intracellular environment from the extracellular environment. also known as cell membrane cytosol, the aqueous fluid that surrounds the organelles inside a cell
ribosomes
small RNA protein structure that is the site of protein synthesis. they either float freely in the cytoplasm or are attached to the rough endoplasmic reticulum
DNA- deoxyribose nucleic acid
a double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival
membrane bound organelle
structure within a cell that is enclosed by a phospholipid bilayer
chromosome
the structure made of protein and nucleic acids that carries genetic information
nucleus
a double membrane- bound organelle that protects and confines the genetic information (DNA) of a cell. Inside the nucleus is a smaller structure known as the nucleolus which is the site of ribosome production
plasmid
a small, circular loop of DNA that is separate from a chromosome, typically found in bacteria
somatic cell
ny cell that is not a reproductive cell (such as sperm and egg cells). Somatic cells are diploid (2n), meaning they contain two sets of chromosomes – one inherited from each parent
mitosis
the cell division phase which involves the complete separation of sister chromatids and nuclei
germline cells
cells that are involved in the generation of gametes in eukaryotes
gametes
reproductive cells that arise from germline cells that contain half the genetic material (n) of a somatic cell. In humans, gametes are sperm and eggs
meiosis
a specialised form of cell division used to produce gametes in sexually-reproducing organisms
binary fission
the method of cell replication used by prokaryotes
micrometres- μm
unit of measurement where 1 mm =1000μm
table 2 Characteristics of each kingdom
domains and kingdoms of prokaryotes
domains- archaea and bacteria
kingdoms- archaea and bacteria
domains and kingdoms of eukaryotes
domains- eukarya
kingdoms- Animalia, Fungi, Plantae and Protista
organelle
a cellular structure that performs specific functions
cytosol
the aqueous fluid that surrounds the organelles inside a cell
cytoplasm
the cytosol and organelles inside the plasma membrane, excluding the nucleus